Willis Tower Skyscraper and the Glass Ledge

Willis Tower, formerly christened ‘Sears Tower’ is a centre of business and the tallest skyscraper in Chicago, Illinois, United States. Chicago’s skyline owned Willis Tower as the world’s tallest building until the inauguration of the Burj Khalifa in Dubai, U74AE. Currently it is on the second place among the world’s tallest buildings, is the tallest skyscraper in the western hemisphere and the tallest building in the United States.

Willis Tower has 108-storeys and stands at 1,450 feet (443 meters) - 1,730 feet (520 meters), which include the heights of twin antenna towers. The Tower offers 3.8 million square feet of space inside for retail and business purposes; and it cost more than $150 million to create this building.

Salient Features:

• The structure is formed from 9 bundled square tubes, each 75 feet wide with no columns between the core and perimeter. Two of the tubes are 50 floors high, two are 66 floors, three are 90, and two are 108.
• The construction with separate tubes provides lateral strengths to withstand the strong Chicago wind loads, as each tube only needs to take a part of the pressure.
• Facades consist of 28-acres of black anodized aluminium panels and approximately 16,100 bronze-tinted windows.
• Six roof-mounted robotic window washing machines are used to clean all 16,100 windows.
• The tower has a pressure lock at the freight entrance to combat the 'stack effect' generated by the differential in air pressure caused by cold air meeting warm air in the building.
• Includes world's fastest observatory elevators at 1600 feet per minute.
• Solar panels on the 90th floor roof of this tower are used to heat water for restrooms.
• Smart lighting systems installed here will automatically dim when enough sunlight is available inside.
• Includes 25,000 miles (40,223 kilometres) of electrical cable and approximately 43,000 miles (69,200 kilometres) of telephone cables.

Skydeck

The most attractive feature of the Willis Tower is the observation deck, or the “Skydeck”, which is 1,353 feet (412 meters) high above the ground. The Skydeck occupies the 103rd floor, the highest non-mechanical floor in the building. It has its own entrance on Jackson Boulevard, and attracts approximately 1.5 million visitors per year.

Skydeck offers the best views of Chicago and it is possible to see four states - Illinois, Indiana, Michigan and Wisconsin, as the range of view is 40 - 50 miles (65 - 80 kilometres) from here.

Another attraction at the Skydeck is 'the Ledge', a glass balcony extending 4.3 ft from where one can look straight down. The glass balcony is 10ft high and 10ft wide, and can hold five tons of weight with its 1.5 inches-thick glass. The transparent walls, floor and ceiling leave visitors with a feeling of floating in air.

Each glass box is comprised of three layers of glass laminated into one seamless unit. The low-iron, clear glass is fully tempered and heat-soaked for durability. In addition, the motorized system that projects and retracts the boxes from the building utilizes steel Linear Beams.

This Skydeck is cold, almost icy to the touch and gives a rather eerie feeling when looked at!

Glass and Glass Facades in India

As time passes, trends, lifestyles, and even the environment undergoes tremendous change; buildings and construction material being no exception to this rule. Cursory observation is sufficient proof for this statement; architecture today is devoid of the conventional cement and steel and replete with glass; a phenomenon less than a decade old.The emergence of architectural glass as a high-performance building material is the key determinant of this change. Glass is now a protective sheath that protects occupants of a building from heat, noise, fire, and even from dirt and grime through self-cleaning properties. Reflective glass controls solar radiations, low-e glass acts as a thermal insulator, extra clear float glass serves as partitions, and then there is switchable glass, tinted glass, fire safety glass and so on. Apart from façade glazing, all these glass types can be used on doors, windows, curtain walls, balustrade, and even skylights. Glass façade systems offer versatility as well as functionality, while enabling a wide range of design possibilities, including custom printing, shading/fritting, and more.

Let us go through the details of some fantastic structures in glass in the country.

International Convention Centre, Pune
Located in the heart of Pune, the International Convention Centre at Pune serves as Southeast Asia’s largest convention centre. The façade of this building comprises insulated glass and aluminum cladding; the choice of these materials allowing for ease of maintenance. A central portion of the structure is completely glazed, imparting an iconic element to the overall configuration.

i-Think Campus, Thane
i-Think is a proposed IT Park at Thane spread over a 5 acre property with a total built up area of approximately 850,000 sq ft. The design, visualized and manifested by Aedas Architects, comprises structural glazing, skylights, an entrance canopy and a shop front glazing. The building comprises two independent blocks connected by sky terraces located at every two floors which create a feeling of spaciousness and brightness.

i-Think Campus, Kanjurmar, Mumbai
This is also a proposed IT Park comprising 4 blocks spread over an area of 1.8 million sq ft and located at Kanjurmarg, Mumbai. Each building shelters retail outlets at two levels and parking slots over three levels, in addition to office space over ten floors. The façade elements include composite glazing, aluminum cladding, glass enclosures, suspended glazing, entrance canopy, stone cladding and entrance glazing.

Lodha Excellus, Mahalakshmi, MumbaiThis is a proposed corporate office in Mumbai meant for clients based out of the Apollo Mills compound. The façade is made up of structural glazing, terrace awning, aluminum fins, shop front glazing and stone cladding. Vertical structures in stone on two sides of the building add visual appeal.

Inorbit Mall, Hyderabad
This Retail Mall is in the Cyberabad region of Hyderabad in Andhra Pradesh and has a total built up area of 800,000 square feet. The Mall has a unique atrium skylight with a combination of metal roof and laminated glass.

Taj ITPL Hotel, Bangalore
Taj ITPL Hotel is a 250 room hotel located in Whitefield, the IT hub of Bangalore. The facade envelope comprises of a combination of coloured laminated glass, insulated glass and ceramic frit glass. The design incorporates horizontal LED rope lights for the curtain wall in a staggered pattern and vertical cold cathode lights at the suspended glazing area. The canopy comprises glass encased in a steel sub-structure.

Park Hyatt, HyderabadThe Park Hyatt in Hyderabad includes a rain screen design featuring indigenous Indian granite cladding, extruded terra cotta sunscreens, low-e insulated glass and architectural metal accents. The atrium features a high span skylight with patterned glass for maximum day lighting balanced with sun control.

Sun Court Residential Towers, Noida
Sun Court Residential Towers at Greater Noida comprises of four residential towers, all unique in their features. They include external façade elements such as curtain walls with sunshade devices, vertical sunshades, flying glass buttresses at terrace level, double height lobby, entrance canopy, glass railing and skylight at terrace floor level.

Banyan Park, Mumbai

The façade of Banyan Park at Andheri in Mumbai is infused with glazed window walls and curtain walls strategically placed to take advantage of natural daylighting while minimizing direct sun exposure. The facade design features a rain screen concept that facilitates the ease of rinsing during rainfall to keep the facade clean.